The Jaguar Mk I  1956-1959

Years 1956-1959 (2.4), 1957-1959 (3.4) (a very few cars were made in 1960)
Notes The 2.4 litre was launched at the 1955 Motor Show. It was designed to fill the product gap between Jaguars large luxury cars (the then current MK VII), and the sportscar XK range). Jaguar realized that they had two problems with their existing two ranges, 1)  that they sold into market segments easily affected by a recession - luxury and sports vehicles, and 2), there was too much dependence on foreign sales, which could be closed overnight at the whim of a foreign government. What was needed was a car that could sell into a larger market, and what is more could sell quite strongly in the home market. It was not intended to be a main stream family car, but more a car that could be aspired to by the ordinary motorist, which was a segment remarkably devoid of competition in the mid 1950's.

The new car broke entirely new ground for Jaguar by being of monococque construction, albeit in hindsight, immensely over-engineered. Although an all new car, it featured a strong family likeness to both of the other ranges, with an XK like front end styling grafted to a center and rear section that  looked remarkably MK,  although the latters pronounced swept wing line from front to rear was omitted, in favor of a straight line styling. According to some sources it was intended to resurrect a variant of the 2 litre 4 cylinder engine that was to have powered the XK100 if it had ever been marketed, but in the end a new 2.4 litre version of the XK 6 cylinder engine was developed, by shortening the stroke (and the height) of the standard 3.4 litre engine.

The 3.4 variant was most likely produced initially for the US market, where the 2.4 would have been viewed as underpowered. It soon became popular in the home market too, and as the production figues show, sold as well at home as abroad. When the 3.4 was first produced in 1957 the disc brakes were not ready for production, and so early models were fitted with servo assisted drums. Conversion kits were later made available for owners to upgrade their brakes on both 2.4 and 3.4 models, The 3.4 was fitted with the engine from the XK140/150, producing the same 210 bhp when fitted with the B cylinder head and SU carburettors. Cooling had to be increased, so the 3.4 was fitted with a larger grille, similar to the one on the concurrent XK150. This soon became standard on the 2.4 as well to rationalize production. (the original 2.4 grille was similar to the XK140 item). The other main distinguishing external feature was the fitment of cut-away rear wheel spats, so that wire wheels could be fitted and cooling to the marginal drum brakes increased.. Again this was soon fitted to the 2.4 as well

Description 4 door sedan (saloon)
Colors See the compact sedan colors page
Model Engine Bore/Stroke Power
2.4 2483cc 6 cyl twin overhead camshaft 83 x 76.5 mm 112 bhp @ 5750 rpm
3.4 3442cc 6 cyl twin overhead camshaft 83 x 106 mm 210 bhp @ 5500 rpm
2.4 Twin Solex downdraught
3.4 Twin SU HD6
All engines are versions of the Jaguar XK type DOHC inline 6
Brakes Initially hydraulic drum, 4 wheel vacuum assisted discs were optional but in practice almost standard from late 1957.

(Various sources differ, slightly)
2.4 right hand drive 16250  
2.4 left hand drive 3742 Total 2.4  19992
3.4 right hand drive 8945    
3.4 left hand drive 8460 Toral 3.4  17405
All models 37397  
2.4 3024 pounds
3.4 3136 pounds
Length 15 feet 0 3/4 inches
Height 4 feet 9 1/2 inches 
Width 5 feet 6 3/4 inches 
Top speed 101 mph (2.4) 120 (3.4)
Wheelbase 107.375 inches
Transmission 4-speed manual. Overdrive optional. Also available, Borg Warner 3 speed automatic on the 3.4 and later 2.4's
Front Independent. Coil springs, wishbones and anti-roll bar
Rear Live axle, radius arms, Panhard rod, half elliptic leaf springs.
Chassis Numbers
Additional codes with number
DN suffix means car is fitted with overdrive
BW suffix means car is fitted with automatic gearbox
2.4 900001-916250 (RHD models)
940001-943742 (LHD models).
3.4 970001-978945 (RHD models)
985001-993461 (LHD models)
Engine Numbers See the compact sedans engine number page
Standard Equipment Leather seats, fog/spot lights.Hub caps (on standard steel wheels)
Options A rare "Standard" version was cataloged, which was a 2.4 without Rev Counter, heater, Jaguar Mascot, Windshield Washers, Foglights, etc. At only 21 pounds sterling less than the "Special Equipment" model, it appears to have sold in miniscule numbers, and it was the SE car that became the standard! 

Automatic transmission on the 3.4 (and 2.4 after the 3.4's introduction), overdrive, wire wheels (in body color, chrome or stove enamel), wheel trims for steel wheels (available either as trim rings for use with standard hubcap, or a complete wheeltrim ring which replaced the hubcap), laminated windshield, various radios, Twin exhaust system, and three levels of Tuning Kits for the 2.4  Disc brakes and conversion kits from drum to disc were available. In addition special paint finishes were available to special order.

Wire wheels were 15" and had 60 spokes until the beginning of 1959, when they were changed to stronger 72 spoke wheels.